This invention relates generally to fifth wheel assemblies for coupling semi-trailers to tractors. More particularly the invention relates to a method and apparatus for assisting the precise positionment of an adjustable fifth wheel carrier assembly.
Large highway freight trailers are usually coupled to an associated tractor by means of a fifth wheel assembly whereby the tractor rear drive axles directly support a portion of the trailer load burden. Usually, the fifth wheel couple and support point is located along the length of the tractor between the rear drive wheels and the front steering wheels thereby distributing the front trailer burden between the driver and the steering wheels. The exact percentage of load desirably placed upon the front steering wheels is a variable dependent upon many factors including the road surface, the tractor equipment, the weather, the weight of the trailer and the whim of the driver.
Some degree of control over these variables is provided by a fifth wheel receiver that is mounted on a slide carriage assembly. The carriage assembly is rail guided and includes an anchoring mechanism for securing the slidable assembly at the desired point along the tractor length between the driving and steering wheel axles.
Finding and setting the fifth wheel carriage assembly at the desired point can be tedious, time consuming, and frustrating. The general procedure is to lock the trailer brakes, release the fifth wheel carriage anchor mechanism, and then drive the tractor forward or reverse until the fifth wheel carriage is at the desired point whereupon the anchoring mechanism is reengaged to secure the fifth wheel carriage at the desired location. When the trailer is heavily loaded, stopping the tractor at the exact location desired for the fifth wheel assembly can be difficult.
It is an object of the present invention, therefore, to teach a method for precisely controlling the terminal point of a position changeable fifth wheel carriage.
Another object of the present invention is to provide a small, conveniently carried, tool adapted for convenient positionment on a fifth wheel carriage slide rail rack as a selectively positionable abutment structure.
Another object of the present invention is to provide a position adjustable fifth wheel carriage assembly having convenient and rapid redistribution of trailer weight on the drive and steering axles of the tractor.
A still further object of the present invention is to provide a method and apparatus for adjusting the position of a fifth wheel slide carriage in one single, positively controlled movement of the tractor.